Sofa



FIG. 1 is a front perspective view of a sofa showing my design;

FIG. 2 is a top perspective view thereof;

FIG. 3 is a back perspective view thereof; and,

FIG. 4 is a side elevation view thereof, an opposite side elevation view being a mirror image thereof.

The broken lines shown on the sofa are understood to represent stitching. 

The ornamental design for a sofa, as shown and described. 